By Dani Blum
Cases of norovirus — a common, contagious virus that can induce vomiting and diarrhea — are generally rising across the United States, according to new data from the Centers for Disease Control and Prevention. Norovirus is spreading elsewhere, too; in England, cases are reportedly 66% higher than the average around this time of year, with the largest increase among people ages 65 and older.
Norovirus outbreaks are common in places where people are close together and touch the same surfaces — such as day care centers and cruise ships, said Dr. Camille Sabella, a pediatric infectious diseases specialist at Cleveland Clinic Children’s. But anyone anywhere can contract the virus. Here’s what to know about symptoms, treatment and prevention.
What is norovirus?
Norovirus is a viral infection that inflames your intestines, Sabella said. People sick with norovirus typically feel nauseated, have diarrhea and throw up; they may also experience stomach pain. Some people develop a fever. Symptoms usually clear up after one to three days, said Dr. Karen Krueger, an infectious diseases specialist at Northwestern Medicine.
“It comes in quickly and it leaves quickly,” Sabella added.
For many people, the illness is usually mild, though extremely unpleasant. But norovirus can cause young children, seniors, and those with compromised immune systems or existing health conditions to become severely dehydrated. In rare cases, people can become hospitalized or die.
How does norovirus spread?
The virus is highly transmissible: Infected people can shed billions of norovirus particles, according to the CDC, and it takes fewer than 100 particles to make another person sick. What’s more, people can continue to shed the virus even after they’re feeling better, Sabella said; in some cases, they can transmit the virus for up to two weeks after their symptoms go away. In fact, people are most contagious when they have symptoms and in the days immediately after those symptoms fade.
Norovirus can spread in a few insidious ways. The most common route is through close contact with an infected person, said Dr. Jennifer Lighter, an infectious diseases specialist and hospital public health researcher at NYU Langone Health. For example, parents can get sick by changing a diaper and then touching their mouths or by ingesting tiny, often unnoticeable particles in the air transmitted from a vomiting child. “You see the whole family get sick at the same time,” Lighter said. You can also get norovirus if you shake a sick person’s hand and then touch your mouth.
The virus can also spread via surfaces: If an infected person vomits and touches a doorknob, and then you reach for that doorknob and touch your mouth (which happens more often than you might think), there’s a good chance you will pick up norovirus. It’s not clear just how long norovirus can survive on a surface, Sabella said.
Norovirus can also contaminate food and water, Sabella said. For example, infected people might have tiny traces of feces on their hands and then touch food, or a septic tank might leak into a well. Norovirus is the most common culprit of foodborne illnesses in the country, Krueger said.
How do you know whether it’s norovirus or food poisoning (or something else)?
Most of the time, you won’t be able to tell the difference, Sabella said. And generally, it doesn’t matter. Unless you’re sick enough to go the hospital, a doctor typically won’t recommend getting a diagnostic test because symptom management is usually similar for all manner of stomach bugs.
There are PCR tests for stool samples available, Krueger said, but doctors use those tests only in rare instances.
How do you treat norovirus?
There is no treatment for norovirus, Lighter said; you just need a few days to let the infection run its course. But there are ways to manage your symptoms.
Above all, it’s crucial to get enough fluids, as the liquid you lose from vomiting and having diarrhea can cause dehydration — which, in turn, can lead to serious complications and potentially hospitalization. Water can help keep you hydrated, but you may want to reach for an electrolyte drink, especially if you are vomiting, Sabella said, to avoid an electrolyte imbalance.
How do you know if you’re adequately hydrated? With babies, Sabella said, look for frequent, wet diapers. Children and adults should be urinating regularly and their pee should be a light, clear yellow, Krueger said. Keep a close eye on infants and older people, she added. If they are acting lethargic, it may be a sign that they are extremely dehydrated and that you should seek medical attention.
Don’t force yourself to eat when you’re still throwing up frequently, Sabella said, but once the vomiting subsides, opt for bland foods such as bananas and toast until you feel better.
Can you get norovirus multiple times?
Yes. (Sorry.) There are numerous strains of norovirus, so it’s possible to get infected more than once. You will probably have some short-term protection from the virus after you recover, Sabella said, but because norovirus moves through the body so quickly, your immune system doesn’t have time to form lasting defenses against it. Fortunately, though, subsequent bouts of the virus tend to be less severe if they occur in the same season, Sabella said.
How can I avoid getting norovirus?
The most important thing you can do is wash your hands frequently with warm water and soap, Sabella said. Don’t use hand sanitizer or alcohol sprays, such as those from Purell, in lieu of washing your hands because they are not as effective as soap and water, Lighter added.
Fruits and vegetables are common sources of transmission, so you should wash them before consuming, Krueger said.
If you’re around a sick family member or taking care of someone, wipe down common surfaces such as door handles and bathroom faucets, Sabella said. Most household disinfectants do not kill norovirus, Lighter said, so make sure you’re using bleach.